ALBANY, N.Y. (NEWS10)- Nearly 100% of COVID-19 cases sampled between September 26 and October 9, by New Yorks Wadsworth Center were positive for the Delta variant. The variant has outpaced all other variants diminishing their existence steadily since late May when a mere 3.5% of cases tested positive for Delta.

New York recently updated its COVID websites sharing additional information on COVID including breakthrough cases, variant information, hospitalization summaries, and positive tests over time with a seven-day positive testing rate per 1,000 people which can be broken down to the county level.

The chart below shows the growth of the Delta variant in New York since May 22.

May 223.5%
June 56.3%
June 1929.8%
July 354.8%
July 1782.1%
July 3195.9%
August 1498.4%
August 2898.9%
September 1199.4%
September 2599.6%
October 999.7%
Source: NYS COVID-19 Variant Data

The Alpha variant was the most prevalent on May 22 (53.4%) and the second most prevalent was the Iota variant (24.4%). The Alpha along with the Beta and Gamma variants were the top three strains at the beginning of the pandemic, according to the Centers for Disease Control and Prevention (CDC). The Iota variant was identified in late February of this year.

The CDC has four designations for variants based on its potential threat:

The Alpha and Iota variants are both designated as VBM’s. The Alpha variant was discovered in the United Kingdom beginning in September 2020, according to the World Health Organization. The Iota variant was largely found in the U.S., particularly New York, according to

The only variant with a designation higher than VBM is the Delta variant, which is labeled a VOC. It received this classification because it spreads faster than other strains, can cause more serious illness, and renders some monoclonal antibody treatments less effective at treating it, the CDC said.

The table below demonstrates how the Delta variant overtook the Alpha and Iota strains between May and October. The Alpha and Iota strains blinked out of existence as the percentage of the Delta variant grew.

May 2255%24.4%3.5%
June 553.2%16.3%6.3%
June 1935.1%5.7%29.8%
July 317.5%2.8%54.8%
July 173.7%.8%82.1%
July 31.9%95.9%
August 14.2%98.4%
August 28.1%98.9%
September 11.1%99.4%
September 2599.6%
October 999.7%
Source: NYS COVID-19 Variant Data

NEWS10 has been reporting on the number of COVID cases in Capital Region counties since the beginning of the pandemic and the number of vaccinations since early 2021. In recent weeks, NEWS10 also started investigating the number of breakthrough cases upon noticing some counties like Albany County, were reporting more than 40% of new cases were breakthroughs.